/**
 * 读取cookie
 * @param {*} name 
 */
function getCookie(name){
    var arr,reg=new RegExp("(^| )"+name+"=([^;]*)(;|$)");
    if(arr=document.cookie.match(reg))
        return unescape(arr[2]);
    else
        return null;
}

/**
 * 设置cookie
 * @param {*} name 
 * @param {*} value 
 */
function setCookie(name,value) { 
    var Days = 30; 
    var exp = new Date(); 
    exp.setTime(exp.getTime() + Days*24*60*60*1000); 
    document.cookie = name + "="+ escape (value) + ";expires=" + exp.toGMTString(); 
} 
//删除cookies 
function delCookie(name) { 
    var exp = new Date(); 
    exp.setTime(exp.getTime() - 1); 
    var cval=getCookie(name); 
    if(cval!=null) 
        document.cookie= name + "="+cval+";expires="+exp.toGMTString(); 
} 
/**
 * 删除所有的cookie
 */
function clearCookie(){ 
    var keys=document.cookie.match(/[^ =;]+(?=\=)/g); 
    if (keys) { 
    for (var i = keys.length; i--;) 
        document.cookie=keys[i]+'=0;expires=' + new Date( 0).toUTCString() 
    } 
} 